H2P4: PHOTON EMISSION

Question

An electron in Li2+ falls from n = 2 to the ground state. Calculate the wavenumber, (νˉ), of the emitted photon.

Answer 1

1/wavelength = wave number = 9*1.09737E7(1/1 - 1/4) =
That comes from
1/wavelength = RZ^2(1/n1^2 - 1/n2^2)
n1 = 1 and 1^2 = 1
n2 = 2 and 2^2 = 4
R = 1.09737E7
Z = atomic number = 3^2 = 9